Vascular embolization with an expansible implant

ABSTRACT

A vascular implant formed of a compressible foam material has a compressed configuration from which it is expansible into a configuration substantially conforming to the shape and size of a vascular site to be embolized. Preferably, the implant is formed of a hydrophilic, macroporous foam material, having an initial configuration of a scaled-down model of the vascular site, from which it is compressible into the compressed configuration. The implant is made by scanning the vascular site to create a digitized scan data set; using the scan data set to create a three-dimensional digitized virtual model of the vascular site; using the virtual model to create a scaled-down physical mold of the vascular site; and using the mold to create a vascular implant in the form of a scaled-down model of the vascular site. To embolize a vascular site, the implant is compressed and passed through a microcatheter, the distal end of which has been passed into a vascular site. Upon entering the vascular site, the implant expands in situ substantially to fill the vascular site. A retention element is contained within the microcatheter and has a distal end detachably connected to the implant. A flexible, tubular deployment element is used to pass the implant and the retention element through the microcatheter, and then to separate the implant from the retention element when the implant has been passed out of the microcatheter and into the vascular site.

CROSS REFERENCE TO RELATED APPLICATION

This application is a Continuation of application Ser. No. 10/320,033,filed Dec. 16, 2002, issuing on Apr. 10, 2007 as U.S. Pat. No.7,201,762, which is a Continuation of application Ser. No. 09/730,071;filed Dec. 5, 2000, now U.S. Pat. No. 6,500,190, which is a Continuationof application Ser. No. 09/110,816; filed Jul. 6, 1998, now U.S. Pat.No. 6,165,193.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable

BACKGROUND OF THE INVENTION

The present invention relates to the field of methods and devices forthe embolization of vascular aneurysms and similar vascularabnormalities. More specifically, the present invention relates to (a)an expansible vascular implant that is inserted into a vascular sitesuch as an aneurysm to create an embolism therein; (b) a method ofmaking the expansible implant; and (c) a method and an apparatus forembolizing a vascular site using the implant.

The embolization of blood vessels is desired in a number of clinicalsituations. For example, vascular embolization has been used to controlvascular bleeding, to occlude the blood supply to tumors, and to occludevascular aneurysms, particularly intracranial aneurysms. In recentyears, vascular embolization for the treatment of aneurysms has receivedmuch attention. Several different treatment modalities have beenemployed in the prior art. U.S. Pat. No. 4,819,637—Dormandy, Jr. et al.,for example, describes a vascular embolization system that employs adetachable balloon delivered to the aneurysm site by an intravascularcatheter. The balloon is carried into the aneurysm at the tip of thecatheter, and it is inflated inside the aneurysm with a solidifyingfluid (typically a polymerizable resin or gel) to occlude the aneurysm.The balloon is then detached from the catheter by gentle traction on thecatheter. While the balloon-type embolization device can provide aneffective occlusion of many types of aneurysms, it is difficult toretrieve or move after the solidifying fluid sets, and it is difficultto visualize unless it is filled with a contrast material. Furthermore,there are risks of balloon rupture during inflation and of prematuredetachment of the balloon from the catheter.

Another approach is the direct injection of a liquid polymer embolicagent into the vascular site to be occluded. One type of liquid polymerused in the direct injection technique is a rapidly polymerizing liquid,such as a cyanoacrylate resin, particularly isobutyl cyanoacrylate, thatis delivered to the target site as a liquid, and then is polymerized insitu. Alternatively, a liquid polymer that is precipitated at the targetsite from a carrier solution has been used. An example of this type ofembolic agent is a cellulose acetate polymer mixed with bismuth trioxideand dissolved in dimethyl sulfoxide (DMSO). Another type is ethyleneglycol copolymer dissolved in DMSO. On contact with blood, the DMSOdiffuses out, and the polymer precipitates out and rapidly hardens intoan embolic mass that conforms to the shape of the aneurysm. Otherexamples of materials used in this “direct injection” method aredisclosed in the following U.S. Pat. No. 4,551,132—Pásztor et al.; U.S.Pat. No. 4,795,741—Leshchiner et al.; U.S. Pat. No. 5,525,334—Ito etal.; and U.S. Pat. No. 5,580,568—Greff et al. The direct injection ofliquid polymer embolic agents has proven difficult in practice. Forexample, migration of the polymeric material from the aneurysm and intothe adjacent blood vessel has presented a problem. In addition,visualization of the embolization material requires that a contrastingagent be mixed with it, and selecting embolization materials andcontrasting agents that are mutually compatible may result inperformance compromises that are less than optimal. Furthermore, precisecontrol of the deployment of the polymeric embolization material isdifficult, leading to the risk of improper placement and/or prematuresolidification of the material. Moreover, once the embolization materialis deployed and solidified, it is difficult to move or retrieve.

Another approach that has shown promise is the use of thrombogenicmicrocoils. These microcoils may be made of a biocompatible metal alloy(typically platinum and tungsten) or a suitable polymer. If made ofmetal, the coil may be provided with Dacron fibers to increasethrombogenicity. The coil is deployed through a microcatheter to thevascular site. Examples of microcoils are disclosed in the followingU.S. Pat. No. 4,994,069—Ritchart et al.; U.S. Pat. No. 5,133,731—Butleret al.; U.S. Pat. No. 5,226,911—Chee et al.; U.S. Pat. No.5,312,415—Palermo; U.S. Pat. No. 5,382,259—Phelps et al.; U.S. Pat. No.5,382,260—Dormandy, Jr. et al.; U.S. Pat. No. 5,476,472—Dormandy, Jr. etal.; U.S. Pat. No. 5,578,074—Mirigian; U.S. Pat. No. 5,582,619—Ken; U.S.Pat. No. 5,624,461—Mariant; U.S. Pat. No. 5,645,558—Horton; U.S. Pat.No. 5,658,308—Snyder; and U.S. Pat. No. 5,718,711—Berenstein et al.

The microcoil approach has met with some success in treating smallaneurysms with narrow necks, but the coil must be tightly packed intothe aneurysm to avoid shifting that can lead to recanalization.Microcoils have been less successful in the treatment of largeraneurysms, especially those with relatively wide necks. A disadvantageof microcoils is that they are not easily retrievable; if a coilmigrates out of the aneurysm, a second procedure to retrieve it and moveit back into place is necessary. Furthermore, complete packing of ananeurysm using microcoils can be difficult to achieve in practice.

A specific type of microcoil that has achieved a measure of success isthe Guglielmi Detachable Coil (“GDC”). The GDC employs a platinum wirecoil fixed to a stainless steel guidewire by a solder connection. Afterthe coil is placed inside an aneurysm, an electrical current is appliedto the guidewire, which heats sufficiently to melt the solder junction,thereby detaching the coil from the guidewire. The application of thecurrent also creates a positive electrical charge on the coil, whichattracts negatively-charged blood cells, platelets, and fibrinogen,thereby increasing the thrombogenicity of the coil. Several coils ofdifferent diameters and lengths can be packed into an aneurysm until theaneurysm is completely filled. The coils thus create and hold a thrombuswithin the aneurysm, inhibiting its displacement and its fragmentation.

The advantages of the GDC procedure are the ability to withdraw andrelocate the coil if it migrates from its desired location, and theenhanced ability to promote the formation of a stable thrombus withinthe aneurysm. Nevertheless, as in conventional microcoil techniques, thesuccessful use of the GDC procedure has been substantially limited tosmall aneurysms with narrow necks.

Still another approach to the embolization of an abnormal vascular siteis the injection into the site of a biocompatible hydrogel, such as poly(2-hydroxyethyl methacrylate) (“pHEMA” or “PHEMA”); or a polyvinylalcohol foam (“PAF”). See, e.g., Horák et al., “Hydrogels inEndovascular Embolization. II. Clinical Use of Spherical Particles”,Biomaterials, Vol. 7, pp. 467-470 (November, 1986); Rao et al.,“Hydrolysed Microspheres from Cross-Linked Polymethyl Methacrylate”, J.Neuroadiol., Vol. 18, pp. 61-69 (1991); Latchaw et al., “Polyvinyl FoamEmbolization of Vascular and Neoplastic Lesions of the Head, Neck, andSpine”, Radiology Vol. 131, pp. 669-679 (June, 1979). These materialsare delivered as microparticles in a carrier fluid that is injected intothe vascular site, a process that has proven difficult to control.

A further development has been the formulation of the hydrogel materialsinto a preformed implant or plug that is installed in the vascular siteby means such as a microcatheter. See, e.g., U.S. Pat. No.5,258,042—Mehta and U.S. Pat. No. 5,456,693—Conston et al. These typesof plugs or implants are primarily designed for obstructing blood flowthrough a tubular vessel or the neck of an aneurysm, and they are noteasily adapted for precise implantation within a sack-shaped vascularstructure, such as an aneurysm, so as to fill substantially the entirevolume of the structure.

There has thus been a long-felt, but as yet unsatisfied need for ananeurysm treatment device and method that can substantially fillaneurysms of a large range of sizes, configurations, and neck widthswith a thrombogenic medium with a minimal risk of inadvertent aneurysmrupture or blood vessel wall damage. There has been a further need forsuch a method and device that also allow for the precise locationaldeployment of the medium, while also minimizing the potential formigration away from the target location. In addition, a method anddevice meeting these criteria should also be relatively easy to use in aclinical setting. Such ease of use, for example, should preferablyinclude a provision for good visualization of the device during andafter deployment in an aneurysm.

SUMMARY OF THE INVENTION

Broadly, a first aspect of the present invention is a device foroccluding a vascular site, such as an aneurysm, comprising a conformalvascular implant, formed of an expansible material, that is compressiblefrom an initial configuration for insertion into the vascular site bymeans such as a microcatheter while the implant is in a compressedconfiguration, and that is expansible in situ into an expandedconfiguration in which it substantially fills the vascular site, therebyto embolize the site, wherein the initial configuration of the implantis a scaled-down model of the vascular site.

In a preferred embodiment, the implant is made of a hydrophilic,macroporous, polymeric, hydrogel foam material, in particular awater-swellable foam matrix formed as a macroporous solid comprising afoam stabilizing agent and a polymer or copolymer of a free radicalpolymerizable hydrophilic olefin monomer cross-linked with up to about10% by weight of a multiolefin-functional cross-linking agent. Thematerial is modified, or contains additives, to make the implant visibleby conventional imaging techniques.

Another aspect of the present invention is a method of manufacturing avascular implant, comprising the steps of: (a) imaging a vascular siteby scanning the vascular site to create a digitized scan data set; (b)using the scan data set to create a three-dimensional digitized virtualmodel of the vascular site; and (c) forming a vascular implant device inthe form of a physical model of the vascular site, using the virtualmodel, the implant being formed of a compressible and expansiblebiocompatible foam material. In a specific embodiment, the forming step(c) comprises the substeps of: (c)(1) using the virtual model to createa scaled-down, three-dimensional physical mold of the vascular site; and(c)(2) using the mold to create a vascular implant in the form of ascaled-down physical model of the vascular site.

In the preferred embodiment of the method of manufacturing the implant,the imaging step is performed with a scanning technique such as computertomography (commonly called “CT” or “CAT”), magnetic resonance imaging(MRI), magnetic resonance angiography (MRA), or ultrasound.Commercially-available software, typically packaged with and employed bythe scanning apparatus, reconstructs the scan data set created by theimaging into the three-dimensional digitized model of the vascular site.The digitized model is then translated, by commercially-availablesoftware, into a form that is useable in a commercially availableCAD/CAM program to create the scaled-down physical mold by means ofstereolithography. A suitable implant material, preferably a macroporoushydrogel foam material, is injected in a liquid or semiliquid state intothe mold. Once solidified, the hydrogel foam material is removed fromthe mold as an implant in the form of a scaled-down physical model ofthe vascular site.

A third aspect of the present invention is a method for embolizing avascular site, comprising the steps of: (a) passing a microcatheterintravascularly so that its distal end is in a vascular site; (b)providing a vascular implant in the form of a scaled-down physical modelof the vascular site, the implant being formed of a compressible andexpansible biocompatible foam material; (c) compressing the implant intoa compressed configuration dimensioned to pass through a microcatheter;(d) passing the implant, while it is in its compressed configuration,through the microcatheter so that the implant emerges from the distalend of the microcatheter into the vascular site; and (e) expanding theimplant in situ substantially to fill the vascular site.

The apparatus employed in the embolization method comprises an elongate,flexible deployment element dimensioned to fit axially within anintravascular microcatheter; a filamentous implant retention elementdisposed axially through the deployment element from its proximal end toits distal end; and an implant device removably attached to the distalend of the retention element.

The implant device, in its preferred embodiment, is formed of amoldable, hydrophilically expansible, biocompatible foam material thathas an initial configuration in the form of a scaled-down physical modelof the vascular site, that is compressible into a compressedconfiguration that fits within the microcatheter, and that ishydrophilically expansible into an expanded configuration in which it isdimensioned substantially to conform to and fill the vascular site.Alternatively, the implant device may be formed of a non-hydrophilicfoam material having an initial configuration that is substantially thesame size and shape as the vascular site, and that restores itself toits initial configuration after it is released from its compressedconfiguration.

The retention element is preferably a flexible wire having a distal endconfigured to releasably engage the implant device while the implantdevice is in its compressed configuration, thus to retain the implantdevice within the distal end of the microcatheter while the distal endof the microcatheter is inserted into the vascular site. The wire ismovable axially with the deployment element in the distal direction toexpose the implant from the distal end of the microcatheter, and ismovable proximally with respect to the deployment element to urge theimplant device against the distal end of the deployment element, therebypush the implant device off of the wire. Thus released into the vascularsite, the implant device expands into an expanded configuration in whichit substantially conforms to and fills the vascular site.

The present invention provides a number of significant advantages.Specifically, the present invention provides an effective vascularembolization implant that can be deployed within a vascular site withexcellent locational control, and with a lower risk of vascular rupture,tissue damage, or migration than with prior art implant devices.Furthermore, the implant device, by being modelled on the actualvascular site in which it is to be implanted, effects a conformal fitwithin the site that promotes effective embolization, and yet itsability to be delivered to the site in a highly compressed configurationfacilitates precise and highly controllable deployment with amicrocatheter. In addition, the method of fabricating the implantdevice, by modeling it on each individual site, allows implant devicesto be made that can effectively embolize vascular sites having a widevariety of sizes, configurations, and (in the particular case ofaneurysms) neck widths. These and other advantages will be readilyappreciated from the detailed description that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart showing a method of manufacturing a vascularimplant in accordance with a preferred embodiment of the manufacturingmethod aspect of the present invention;

FIG. 2 is a perspective view of a vascular implant in accordance with apreferred embodiment of the vascular implant device aspect of thepresent invention, showing the implant in its initial configuration;

FIG. 3 is an elevational view of the implant of FIG. 2, showing theimplant in its compressed configuration;

FIG. 4 is a perspective view of the implant of FIG. 2, showing theimplant in its expanded configuration;

FIG. 5 is a cross-sectional view of an implanting apparatus employed ina method of embolizing a vascular site in accordance with a preferredembodiment of the embolizing method aspect of the present invention; and

FIGS. 6 through 10 are semischematic views showing the steps in a methodof embolizing a vascular site (specifically, an aneurysm) in accordancewith a preferred embodiment of the embolizing method aspect of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

The Method of Manufacturing a Vascular Implant. A first aspect of thepresent invention is a method of manufacturing a vascular implantdevice. The steps of a preferred embodiment of the manufacturing methodare shown as a sequence of descriptive boxes in the flow chart of FIG.1.

The first step, shown in box 10 of FIG. 1, is the step of creating animage of a vascular site, such as an aneurysm, in which an embolizingimplant is to be installed. This imaging step is performed by scanningthe site using any of several conventional imaging techniques, such ascomputer tomography, magnetic resonance imaging (MRI), magneticresonance angiography (MRA), or ultrasound.

The result of the imaging step is a digitized scan data set that isstored in a computer memory, from which the data set is retrieved foroperation of the next step: computerized reconstruction of athree-dimensional digitized virtual model of the vascular site (box 12of FIG. 1). This step of creating a three-dimensional digital model istypically performed by software designed for this purpose that ispackaged with and employed by the imaging apparatus.

The digitized, three-dimensional virtual model is then translated into aform in which it can be employed in a commercially-available CAD/CAMprogram (box 14) which controls a stereolithography process (box 16) tocreate a mold for forming an implant device. The translation of thevirtual model is performed by software that is commercially available,for example, from Cyberform International, Inc., of Richardson, Tex.,and from Stratasys, Inc., of Minneapolis, Minn. The mold (not shown) ispreferably scaled-down from the dimensions of the vascular site, with ascale of about 1:2 to about 1:6, with about 1:4 being preferred.Alternatively, the mold may be made “life size” (i.e., 1:1); that is, afull-size or nearly full-size replica of the vascular site. The mold isused in the fabrication of a vascular implant device by conventionalmolding techniques (box 18).

The Implant Device. A vascular implant device 20, in accordance with thepresent invention, is shown in FIG. 2 as it appears in its uncompressedor precompressed initial configuration after withdrawal from the mold.Preferably, the implant device 20 is molded directly onto the distal endportion of an elongate, flexible, filamentous retention element, such asa retention wire 22, for purposes to be described below. The retentionwire 22 preferably has a distal end that terminates in a knob 24 (FIG.5) for better retention of the implant device 20 thereon.

In the preferred embodiment, the implant device 20 is made of abiocompatible, macroporous, hydrophilic hydrogel foam material, inparticular a water-swellable foam matrix formed as a macroporous solidcomprising a foam stabilizing agent and a polymer or copolymer of a freeradical polymerizable hydrophilic olefin monomer cross-linked with up toabout 10% by weight of a multiolefin-functional cross-linking agent. Asuitable material of this type is described in U.S. Pat. No.5,570,585—Park et al., the disclosure of which is incorporated herein byreference. Another suitable material is a porous hydrated polyvinylalcohol foam (PAF) gel prepared from a polyvinyl alcohol solution in amixed solvent consisting of water and a water-miscible organic solvent,as described, for example, in U.S. Pat. No. 4,663,358—Hyon et al., thedisclosure of which is incorporated herein by reference. Still anothersuitable material is PHEMA, as discussed in the references cited above.See, e.g., Horák et al., supra, and Rao et al., supra. The foam materialpreferably has a void ratio of at least about 90%, and its hydrophilicproperties are such that it has a water content of at least about 90%when fully hydrated.

In a preferred embodiment, the implant device 20, in its initial,precompressed configuration, will have the same configuration as thevascular site, but it will be smaller, by a factor of approximately twoto approximately six. The material of the implant device 20, and itsinitial size, are selected so that the implant device 20 is swellable orexpansible to approximately the size of the vascular site, primarily bythe hydrophilic absorption of water molecules from blood plasma, andsecondarily by the filling of its pores with blood. The result is anexpanded configuration for the implant device 20, as shown in FIG. 4,that is large enough substantially to fill the vascular site.

Alternatively, the implant 20 device can be molded so that in itsinitial, precompressed configuration, it is “life size”, i.e.,approximately the same size as the vascular site. In this case, thepreferred material is a compressible, non-hydrophilic polymeric foammaterial, such as polyurethane. In actual clinical practice, anon-hydrophilic implant device 20 would advantageously be made slightlysmaller than actual life size, to accommodate swelling due to thefilling of the pores.

The foam material of the implant device 20, whether hydrophilic ornon-hydrophilic, is advantageously modified, or contains additives, tomake the implant 20 visible by conventional imaging techniques. Forexample, the foam can be impregnated with a water-insoluble radiopaquematerial such as barium sulfate, as described by Thanoo et al.,“Radiopaque Hydrogel Microspheres”, J Microencapsulation. Vol. 6, No. 2,pp. 233-244 (1989). Alternatively, the hydrogel monomers can becopolymerized with radiopaque materials, as described in Horák et al.,“New Radiopaque PolyHEMA-Based Hydrogel Particles”, J BiomedicalMaterials Research, Vol. 34, pp. 183-188 (1997).

Whatever the material from which the implant device 20 is made, theimplant device 20 must be compressible to a fraction of its initialsize, preferably into a substantially cylindrical or lozenge-shapedconfiguration, as shown in FIG. 3. Compression of the implant device 20can be performed by squeezing it or crimping it with any suitablefixture or implement (not shown), and then “setting” it in itscompressed configuration by heating and/or drying, as is well-known. Thepurpose for this compression will be explained below in connection withthe method of using the implant device 20 to embolize a vascular site.

The Method and Apparatus for Embolizing a Vascular Site. The method ofembolizing a vascular site using the implant device 20 is performedusing an implanting apparatus 30, a preferred embodiment of which isshown in FIG. 5. The implanting apparatus 30 comprises the retentionelement or wire 22, a microcatheter 32, and an elongate, flexible,hollow, tubular element 34 (preferably a coil) that functions as animplant deployment element, as will be described below. With the implantdevice 20 attached to the distal end of the retention wire 22, theproximal end of the retention wire 22 is inserted into the distal end ofthe implant deployment element 34 and threaded axially through theimplant deployment element 34 until the proximal end of the implantdevice 20 seats against, or is closely adjacent to, the distal end ofthe implant deployment element 34. The implant deployment element 34 isdimensioned for passing axially through the microcatheter 32. Thus, theimplant deployment element 34, with the implant device 20 extending fromits proximal end, may be inserted into the proximal end (not shown) ofthe microcatheter 32 and passed axially therethrough until the implantdevice 20 emerges from the distal end of the microcatheter 32, as shownin FIG. 5.

The implant device 20, in its compressed configuration, has a maximumoutside diameter that is less than the inside diameter of themicrocatheter 32, so that the implant device 20 can be passed throughthe microcatheter 32. The implant device 20 is preferably compressed and“set”, as described above, before it is inserted into the microcatheter32.

FIGS. 6 through 10 illustrate the steps employed in the method ofembolizing a vascular site 40 using the implant device 20. The vascularsite 40 shown in the drawings is a typical aneurysm, but the inventionis not limited to any particular type of vascular site to be embolized.

First, as shown in FIG. 6, the microcatheter 32 is threadedintravascularly, by conventional means, until its distal end is situatedwithin the vascular site 40. This threading operation is typicallyperformed by first introducing a catheter guidewire (not shown) alongthe desired microcatheter path, and then feeding the microcatheter 32over the catheter guidewire until the microcatheter 32 is positionedsubstantially as shown in FIG. 6. The catheter guidewire is thenremoved.

The implant deployment element 34, with the implant device 20 extendingfrom its distal end, is then passed through the microcatheter 32, asdescribed above, until the implant device 20 emerges from the distal endof the microcatheter 32 into the vascular site 40, as shown in FIGS. 7and 8. When inserting the implant device 20 into the microcatheter 32, abiocompatible non-aqueous fluid, such as polyethylene glycol, may beinjected into the microcatheter 32 to prevent premature expansion of theimplant device 20 due to hydration, and to reduce friction with theinterior of the microcatheter 32. The implant device 20 thus beingexposed from the microcatheter 32 into the interior of the vascular site40, the pores of the implant device 20 begin to absorb aqueous fluidfrom the blood within the vascular site 40 to release its “set”,allowing it to begin assuming its expanded configuration, as shown inFIG. 9. Then, if the implant device 20 is of a hydrophilic material, itcontinues to expand due to hydrophilic hydration of the implantmaterial, as well as from the filling of its pores with blood. If theimplant device 20 is of a non-hydrophilic material, its expansion is dueto the latter mechanism only.

Finally, when the expansion of the implant device 20 is well underway(and not necessarily when it is completed), the retention wire 22 ispulled proximally with respect to the implant deployment element 34,causing the implant device to be pushed off the end of the installationwire 22 by means of the pressure applied to it by the distal end of theimplant deployment element 34. The implant device 20, now free of theimplanting apparatus 30, as shown in FIG. 10, may continue to expanduntil it substantially fills the vascular site 40. The implantingapparatus 30 is then removed, leaving the implant device 20 in place toembolize the vascular site 40.

While a preferred embodiment of the invention has been described above,a number of variations and modifications may suggest themselves to thoseskilled in the pertinent arts. For example, instead ofcustom-fabricating the implant device for each patient, implant devicesin a variety of “standard” sizes and shapes may be made, and aparticular implant device then selected for a patient based on theimaging of the vascular site. In this case, the fabrication method shownin FIG. 1 would be modified by first creating a three-dimensionaldigital model for each standardized implant, (box 12), and thenproceeding with the subsequent steps shown in boxes 14, 16, and 18.Imaging (box 10) would be performed as an early step in the embolizationprocedure, followed by the selection of one of the standardized implantdevices. This and other variations and modifications are consideredwithin the spirit and scope of the invention, as described in the claimsthat follow.

1. A method of manufacturing a vascular implant, comprising: (a) imaginga vascular site to create a digitized scan data set; (b) creating athree-dimensional virtual model of the vascular site using the digitizedscan data set; (c) forming a vascular implant device in the form of aphysical model of the vascular site using the virtual model; and (d)comprising the vascular implant device into a compressed configuration.2. The method of claim 1, wherein the imaging of the vascular site isperformed by scanning the vascular site.
 3. The method of claim 2,wherein the scanning is performed by a technique selected from the groupconsisting of computer tomography, magnetic resonance imaging; magneticresonance angiography, and ultrasound.
 4. The method of claim 1, whereinthe forming a vascular implant device comprises: (c)(1) creating athree-dimensional physical mold of the vascular site using the virtualmodel; and (c)(2) molding the vascular implant device in the form of thevascular site using the physical mold.
 5. the molding of claim 4,wherein the molding of the vascular implant device includes injecting ahydrophilic polymeric foam material, in a liquid or semi-liquid state,into the molding.
 6. The method of claim 4, wherein the creating of aphysical mold comprises; ( c)(1)(i) translating the virtual model into aform that is usable by CAD/DAM software; and (c)(1)(ii) using theCAD/CAM software to create the physical mold by stereolithography. 7.The method of claim 4, wherein the molding the vascular implant deviceincludes associating the vascular implant with a retention element. 8.The method of claim 1, wherein the vascular implant device is made froma hydrophilic polymeric foam.
 9. The method of claim 1 wherein thecompressing the vascular implant device to the compressed configurationincludes reducing an outside diameter of the vascular implant device toless than an inside diameter of a microcatheter.
 10. The method of claim1 wherein the forming a vascular implant device comprises creating ascaled-down vascular implant device.
 11. A method of embolizing avascular site comprising the steps of: (a) scanning a vascular site tocreate a digitized scan data set; (b) creating a three-dimensionalvirtual model of the vascular site using the digitized scan data set;(c) forming a vascular implant in the form of the vascular site usingthe virtual model; (d) compressing the vascular implant into acompressed configuration; and (e) deploying the vascular implant at thevascular site.
 12. The method of claim 11, wherein the scanning isperformed by a technique selected from the group consisting of computertomography, magnetic resonance imaging, magnetic resonance angiography,and ultrasound.
 13. The method of claim 11, wherein the forming thevascular implant comprises: (c)(1) creating a three-dimensional physicalmold of the vascular site using the virtual model; and (c)(2) moldingthe vascular implant in the form of the vascular site using the physicalmold.
 14. The method of claim 13, wherein the creating of athree-dimensional physical mold comprises; (c)(1)(i) translating thevirtual model into a form that is usable by CAD/DAM software; and(c)(1)(ii) using the CAD/CAM software to create the physical mold bystereolithography.
 15. The method of claim 13, wherein the molding thevascular implant includes injecting a hydrophilic polymeric materialinto the physical mold.
 16. The method of claim 13, wherein the moldingthe vascular implant includes associating a retention element with thevascular implant.
 17. The method of claim 11 wherein the compressing thevascular implant device to the compressed configuration includesreducing an outside diameter of the vascular implant device to less thanan inside diameter of a microcatheter used to deliver said vascularimplant device.
 18. The method of claim 11 wherein the forming avascular implant device comprises creating a scaled-down vascularimplant device.
 19. The method of claim 11 wherein the deploying thevascular implant at the vascular site comprises: (e)(1) passing thevascular implant through a microcatheter; (e)(2) expanding the vascularimplant at the vascular site; and (e)(3) releasing the vascular implantfrom a retention element at the vascular site.
 20. A method ofmanufacturing a vascular implant, comprising: (a) scanning a vascularsite to create a digitized scan data set; (b) creating athree-dimensional virtual model of the vascular site using the digitizedscan data set; (c) forming a vascular implant in the form of a physicalmodel of the vascular site using the virtual model; and (d) associatingthe vascular implant with a retention element, substantiallycontemporaneously to said forming the vascular implant.
 21. The methodof claim 20, wherein the scanning the vascular site is performed by atechnique selected from the group consisting of computer tomography,magnetic resonance imaging; magnetic resonance angiography, andultrasound.
 22. The method of claim 20, wherein the forming the vascularimplant comprises: (c)(1) creating a three-dimensional physical mold ofthe vascular site using the virtual model; and (c)(2) molding thevascular implant in the form of the vascular site using the physicalmold.
 23. The method of claim 22, wherein the creating of thethree-dimensional physical mold comprises; (c)(1)(i) translating thevirtual model into a form that is usable by CAD/DAM software; and(c)(1)(ii) using the CAD/CAM software to create the physical mold bystereolithography.
 24. The method of claim 22, wherein the molding ofthe vascular implant includes injecting a hydrophilic polymeric materialinto the physical mold.
 25. A method of claim 20 further comprisingcompressing the vascular implant to a compressed configuration.
 26. Themethod of claim 25 wherein the compressing the vascular implant to thecompressed configuration includes reducing an outside diameter of thevascular implant device to less than an inside diameter of amicrocatheter.
 27. The method of claim 20 wherein the forming a vascularimplant device comprises creating a scaled-down vascular implant device.